Yield during the first four cycles of a chemical process is shown in the following table. The variables are percentage of concentration (x1) at levels 30, 31, and 32 and temperature (x2) at 140, 142, and 144∘F. Analyze by EVOP methods.

Conditions Cycle (1) (2) (3) (4) (5)

1 60.7 59.8 60.2 64.2 57.5 2 59.1 62.8 62.5 64.6 58.3 3 56.6 59.1 59.0 62.3 61.1 4 60.5 59.8 64.5 61.0 60.1